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Thesis Advisor陈家镛
Degree Grantor中国科学院研究生院
Abstract本文采用电化学研究方法与动力学实验相结合的方法探讨了方铅矿碳酸化转化过程。发现银离子对方铅矿阳极极化过程的强阻抑作用。采用多种电化学方法和物理检测手段研究了Ag~+/PbS表面相互作用以及Ag~+/PbS相互作用对方铅矿阳极极化过程和方铅矿转化过程的影响。结果表明,表面生成的致密无定形S~O和银离子的吸附可能是银离子阻抑作用的原因。采用恒电流极化法考究了溶液组成和晶面取向对方铅矿阳极钝化行为的影响。根据溶解特性的差异证实,在碳酸铵溶液中方铅矿阳极极化生成的元素硫可能是无定形硫。碳酸铅产物层是方铅矿阳极钝化的主要原因。发现溶液中铜离子对方铅矿转化过程起强催化作用。动力学实验表明,铅离子存在下方铅矿碳酸化转化过程在所考究反应时间区间内遵循α = klogt + B的规律。增加碳酸铵和铜离子浓度可提高方铅矿转化率。铜离子催化效果是由于铜氨络离子充当氧“载体”的缘故。电化学实验结果支持这一结论。引入金属腐蚀研究中的线性极化法。测量结果能很好地评价铜离子存在时方铅矿转化率的升高情况。针对本文实验结果,提出强化铅基金矿提金过程和方铅矿碳酸化转化过程的措施。
Other AbstractIn this Dissertation which is hydrometallurgical process developed by this Institute. This is a new and important phenomenon as silver usually coexists with galena in nature. Results indicate that two processes of Ag~+/PbS interaction occur, one is the formation of metallic silver with the oxidation of PbS as shown below Ag(NH_3)_2~+ + e = Ag~+ + 2NH_3 PbS + (NH_4)_2CO_3 = PbCO_3 + 2NH_4~+ + S~+ + 2e while the another one is the adsorption or doping of silver ion on the PbS surface. Effects of concentrations of both silver ions and (NH_4)_2CO_3 in solution and both time and temperature of Ag~+/PbS interaction were taken into account on the anodic polarization of galena. Auger Electron Spectroscopy (AES) were used to detect the presence of silver on the surface. From the above experiments the reason of inhibition in Ag~+/PbS interaction is attributed to the coverage of amorphous sulfur and the adsorption of silver ions at the active site of galena surface. The orientation of crystal face of galena was found, in a preliminary experiment, to have influence on the passivation behavior. The morphology of sulfur produced by anodic oxidation of galena has been found to be related to the formation conditions by analysis of results of X-ray Diffraction studies. The amorphous sulfur is formed with the formation of other solid phase, such as PbCO_3 or PbSO_4, otherwise the crystalline sulfur is formed. The solubility studies also indicate the existence of amorphous sulfur ion anodic oxidation of galena in (NH_4)_2CO_3 solution. Results have shown that the relationship of fraction conversion α with reaction time t can be represented by the following equation. The conversion of galena into PbCO_3 is increased with the increase of the concentration of (NH_4)_2CO_3 and Cu~(++) ions. The catalytic role of cupric ions has been considered to act as "oxygen carrier". The electrochemical studies also support this conclusion. The results of kinetic experiments in the presence of silver ions and other additives were practically in agreement with the results of electrochemical studies.
Document Type学位论文
Recommended Citation
GB/T 7714
龚亚军. 方铅矿碳酸化转化过程的电化学和动力学研究[D]. 中国科学院研究生院,1988.
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